If it's anything like the D21, the clutch pedal assembly and brake pedal assembly are two separate assemblies. You should be able to see where it bolts to the firewall by looking at the engine bay side of the firewall. There may be a couple of bolts under the dash as well.

Here is the D21 clutch assembly. You can see the studs that poke through the firewall. There is a slotted bracket that bolts to a brace in the cab, to the left of the steering wheel.

Here's the brake pedal. You can see the brace that the clutch pedal assembly bolts to. The brake pedal assembly is mouted in a similar fashion.